The direct-sealing diaphragm valves are operated by line pressure .The reinforced rubber diaphragm seals the water passage when line pressure reaches the valve’s control chamber. Relieving the pressure from the control chamber to the atmosphere or to downstream, causes the valve to open. The valve’s only moving component is its diaphragm; no shaft, seals, or bearings are located within the water passage. The valve is made of sturdy, high-quality materials. It is produced in a number of structurally different versions (throttling, built-in solenoid operator, etc), with a wide range of control functions (manual activation, pressure control, etc).